Vehicle washers typically employ rotating brushes or depending cloth strips to clean the vehicle by direct physical contact; see for example U.S. Pat. Nos. 3,812,550, 4,118,820 and 4,470,167, all assigned to Bivens Winchester Corporation of Danville, Va. The brushes typically consist of long plastic strands or bristles which are extended radially outwardly by centrifugal force as the brush rotates. Such vehicle washers have been and still are very popular throughout the United States and in many foreign countries.
It is also well known to wash vehicles by non-contacting apparatus; i.e., apparatus which removes surface dirt by directing a stream of high-pressure fluid at the vehicle. Both robotic devices and hand-held wands have been used for this purpose.
Although many people prefer the non-contacting concept of high-pressure washers, they have found that prior art commercial and home systems have not produced entirely satisfactory results; i.e., pressure systems have simply not proven as effective as brush systems in removing dirt.
On the other hand, pressure washers have advantages over brush systems. Because they do not have direct contact with the vehicle, spray systems cannot mar the vehicle's surface or damage surface projections such as mirrors and antennae. Also, the spray conforms itself to the contours of a vehicle and can penetrate narrow crevices effectively.